November 2025 - Linux-kselftest-mirror

[PATCH v8 00/29] KVM: arm64: Implement support for SME

by Mark Brown

I've removed the RFC tag from this version of the series, but the items that I'm looking for feedback on remains the same: - The userspace ABI, in particular: - The vector length used for the SVE registers, access to the SVE registers and access to ZA and (if available) ZT0 depending on the current state of PSTATE.{SM,ZA}. - The use of a single finalisation for both SVE and SME. - The addition of control for enabling fine grained traps in a similar manner to FGU but without the UNDEF, I'm not clear if this is desired at all and at present this requires symmetric read and write traps like FGU. That seemed like it might be desired from an implementation point of view but we already have one case where we enable an asymmetric trap (for ARM64_WORKAROUND_AMPERE_AC03_CPU_38) and it seems generally useful to enable asymmetrically. This series implements support for SME use in non-protected KVM guests. Much of this is very similar to SVE, the main additional challenge that SME presents is that it introduces a new vector length similar to the SVE vector length and two new controls which change the registers seen by guests: - PSTATE.ZA enables the ZA matrix register and, if SME2 is supported, the ZT0 LUT register. - PSTATE.SM enables streaming mode, a new floating point mode which uses the SVE register set with the separately configured SME vector length. In streaming mode implementation of the FFR register is optional. It is also permitted to build systems which support SME without SVE, in this case when not in streaming mode no SVE registers or instructions are available. Further, there is no requirement that there be any overlap in the set of vector lengths supported by SVE and SME in a system, this is expected to be a common situation in practical systems. Since there is a new vector length to configure we introduce a new feature parallel to the existing SVE one with a new pseudo register for the streaming mode vector length. Due to the overlap with SVE caused by streaming mode rather than finalising SME as a separate feature we use the existing SVE finalisation to also finalise SME, a new define KVM_ARM_VCPU_VEC is provided to help make user code clearer. Finalising SVE and SME separately would introduce complication with register access since finalising SVE makes the SVE registers writeable by userspace and doing multiple finalisations results in an error being reported. Dealing with a state where the SVE registers are writeable due to one of SVE or SME being finalised but may have their VL changed by the other being finalised seems like needless complexity with minimal practical utility, it seems clearer to just express directly that only one finalisation can be done in the ABI. Access to the floating point registers follows the architecture: - When both SVE and SME are present: - If PSTATE.SM == 0 the vector length used for the Z and P registers is the SVE vector length. - If PSTATE.SM == 1 the vector length used for the Z and P registers is the SME vector length. - If only SME is present: - If PSTATE.SM == 0 the Z and P registers are inaccessible and the floating point state accessed via the encodings for the V registers. - If PSTATE.SM == 1 the vector length used for the Z and P registers - The SME specific ZA and ZT0 registers are only accessible if SVCR.ZA is 1. The VMM must understand this, in particular when loading state SVCR should be configured before other state. It should be noted that while the architecture refers to PSTATE.SM and PSTATE.ZA these PSTATE bits are not preserved in SPSR_ELx, they are only accessible via SVCR. There are a large number of subfeatures for SME, most of which only offer additional instructions but some of which (SME2 and FA64) add architectural state. These are configured via the ID registers as per usual. Protected KVM supported, with the implementation maintaining the existing restriction that the hypervisor will refuse to run if streaming mode or ZA is enabled. This both simplfies the code and avoids the need to allocate storage for host ZA and ZT0 state, there seems to be little practical use case for supporting this and the memory usage would be non-trivial. The new KVM_ARM_VCPU_VEC feature and ZA and ZT0 registers have not been added to the get-reg-list selftest, the idea of supporting additional features there without restructuring the program to generate all possible feature combinations has been rejected. I will post a separate series which does that restructuring. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v8: - Small fixes in ABI documentation. - Link to v7: https://lore.kernel.org/r/20250822-kvm-arm64-sme-v7-0-7a65d82b8b10@kernel.o… Changes in v7: - Rebase onto v6.17-rc1. - Handle SMIDR_EL1 as a VM wide ID register and use this in feat_sme_smps(). - Expose affinity fields in SMIDR_EL1. - Remove SMPRI_EL1 from vcpu_sysreg, the value is always 0 currently. - Prevent userspace writes to SMPRIMAP_EL2. - Link to v6: https://lore.kernel.org/r/20250625-kvm-arm64-sme-v6-0-114cff4ffe04@kernel.o… Changes in v6: - Rebase onto v6.16-rc3. - Link to v5: https://lore.kernel.org/r/20250417-kvm-arm64-sme-v5-0-f469a2d5f574@kernel.o… Changes in v5: - Rebase onto v6.15-rc2. - Add pKVM guest support. - Always restore SVCR. - Link to v4: https://lore.kernel.org/r/20250214-kvm-arm64-sme-v4-0-d64a681adcc2@kernel.o… Changes in v4: - Rebase onto v6.14-rc2 and Mark Rutland's fixes. - Expose SME to nested guests. - Additional cleanups and test fixes following on from the rebase. - Flush register state on VMM PSTATE.{SM,ZA}. - Link to v3: https://lore.kernel.org/r/20241220-kvm-arm64-sme-v3-0-05b018c1ffeb@kernel.o… Changes in v3: - Rebase onto v6.12-rc2. - Link to v2: https://lore.kernel.org/r/20231222-kvm-arm64-sme-v2-0-da226cb180bb@kernel.o… Changes in v2: - Rebase onto v6.7-rc3. - Configure subfeatures based on host system only. - Complete nVHE support. - There was some snafu with sending v1 out, it didn't make it to the lists but in case it hit people's inboxes I'm sending as v2. --- Mark Brown (29): arm64/sysreg: Update SMIDR_EL1 to DDI0601 2025-06 arm64/fpsimd: Update FA64 and ZT0 enables when loading SME state arm64/fpsimd: Decide to save ZT0 and streaming mode FFR at bind time arm64/fpsimd: Check enable bit for FA64 when saving EFI state arm64/fpsimd: Determine maximum virtualisable SME vector length KVM: arm64: Introduce non-UNDEF FGT control KVM: arm64: Pay attention to FFR parameter in SVE save and load KVM: arm64: Pull ctxt_has_ helpers to start of sysreg-sr.h KVM: arm64: Move SVE state access macros after feature test macros KVM: arm64: Rename SVE finalization constants to be more general KVM: arm64: Document the KVM ABI for SME KVM: arm64: Define internal features for SME KVM: arm64: Rename sve_state_reg_region KVM: arm64: Store vector lengths in an array KVM: arm64: Implement SME vector length configuration KVM: arm64: Support SME control registers KVM: arm64: Support TPIDR2_EL0 KVM: arm64: Support SME identification registers for guests KVM: arm64: Support SME priority registers KVM: arm64: Provide assembly for SME register access KVM: arm64: Support userspace access to streaming mode Z and P registers KVM: arm64: Flush register state on writes to SVCR.SM and SVCR.ZA KVM: arm64: Expose SME specific state to userspace KVM: arm64: Context switch SME state for guests KVM: arm64: Handle SME exceptions KVM: arm64: Expose SME to nested guests KVM: arm64: Provide interface for configuring and enabling SME for guests KVM: arm64: selftests: Add SME system registers to get-reg-list KVM: arm64: selftests: Add SME to set_id_regs test Documentation/virt/kvm/api.rst | 115 ++++++++--- arch/arm64/include/asm/fpsimd.h | 26 +++ arch/arm64/include/asm/kvm_emulate.h | 6 + arch/arm64/include/asm/kvm_host.h | 169 ++++++++++++--- arch/arm64/include/asm/kvm_hyp.h | 5 +- arch/arm64/include/asm/kvm_pkvm.h | 2 +- arch/arm64/include/asm/vncr_mapping.h | 2 + arch/arm64/include/uapi/asm/kvm.h | 33 +++ arch/arm64/kernel/cpufeature.c | 2 - arch/arm64/kernel/fpsimd.c | 89 ++++---- arch/arm64/kvm/arm.c | 10 + arch/arm64/kvm/config.c | 8 +- arch/arm64/kvm/fpsimd.c | 28 ++- arch/arm64/kvm/guest.c | 252 ++++++++++++++++++++--- arch/arm64/kvm/handle_exit.c | 14 ++ arch/arm64/kvm/hyp/fpsimd.S | 28 ++- arch/arm64/kvm/hyp/include/hyp/switch.h | 175 ++++++++++++++-- arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 110 ++++++---- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 86 ++++++-- arch/arm64/kvm/hyp/nvhe/pkvm.c | 85 ++++++-- arch/arm64/kvm/hyp/nvhe/switch.c | 4 +- arch/arm64/kvm/hyp/nvhe/sys_regs.c | 6 + arch/arm64/kvm/hyp/vhe/switch.c | 17 +- arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 7 + arch/arm64/kvm/nested.c | 3 +- arch/arm64/kvm/reset.c | 156 ++++++++++---- arch/arm64/kvm/sys_regs.c | 141 ++++++++++++- arch/arm64/tools/sysreg | 8 +- include/uapi/linux/kvm.h | 1 + tools/testing/selftests/kvm/arm64/get-reg-list.c | 15 +- tools/testing/selftests/kvm/arm64/set_id_regs.c | 27 ++- 31 files changed, 1327 insertions(+), 303 deletions(-) --- base-commit: 062b3e4a1f880f104a8d4b90b767788786aa7b78 change-id: 20230301-kvm-arm64-sme-06a1246d3636 Best regards, -- Mark Brown <broonie(a)kernel.org>

2 weeks

4
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[PATCH v4 0/3] Support comma-separated symbols and :entry/:exit

by Seokwoo Chung (Ryan)

Extend fprobe to support list-style filters and explicit entry/exit suffixes. Currentyl, fprobe only supports a single symbol (or wildcard) per event. This patch allows users to specify a comma-separated list of symbols. New Syntax: - f:[GRP/][EVENT] func1,func2,func3:entry - f:[GRP/][EVENT] func1,func2,func3:exit Logic changes: - Refactor parsing logic into 'parse_fprobe_spec' - Support '!' prefix for exclusion - Disable BTF lookup ('ctx->funcname = NULL') when a list or wildcard is used, as a single function signature cannot apply to multiple functions. - Reject legacy '%return' suffix when used with lists or wildcards - Update tracefs/README Testing: Verified on x86_64 via QEMU. Checked registration of lists, exclusions, and explicit suffixes. Verified rejection of invalid syntax including trailing commas and mixed legacy/new syntax. Seokwoo Chung (Ryan) (3): docs: tracing/fprobe: Document list filters and :entry/:exit tracing/fprobe: Support comma-separated symbols and :entry/:exit selftests/ftrace: Add accept cases for fprobe list syntax Changes in v4: - Added validation to reject trailing commas (empty tokens) in symbol lists - Added vaildation to reject mixed of list syntax with %return suffix - Refactored parse_fprobe_spec to user __free(kfree) for automatic memory cleanup - Removed the now-unused parse_symbol_and_return function to avoid compiler warnings. - Tigtened %return detection to ensure it only matches as a strict suffix, not a substring - Link to v3: https://lore.kernel.org/lkml/20250904103219.f4937968362bfff1ecd3f004@kernel… Documentation/trace/fprobetrace.rst | 17 +- kernel/trace/trace.c | 3 +- kernel/trace/trace_fprobe.c | 209 ++++++++++++++---- .../ftrace/test.d/dynevent/fprobe_list.tc | 92 ++++++++ 4 files changed, 269 insertions(+), 52 deletions(-) create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc -- 2.43.0

2 weeks

3
8
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[PATCH nf-next] selftests: netfilter: nft_flowtable.sh: Add the capability to send IPv6 TCP traffic

by Lorenzo Bianconi

Introduce the capability to send TCP traffic over IPv6 to nft_flowtable netfilter selftest. Signed-off-by: Lorenzo Bianconi <lorenzo(a)kernel.org> --- .../selftests/net/netfilter/nft_flowtable.sh | 47 +++++++++++++++------- 1 file changed, 33 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/net/netfilter/nft_flowtable.sh b/tools/testing/selftests/net/netfilter/nft_flowtable.sh index 1fbfc8ad8dcdc5db2ab1a1ea9310f655d09eee83..24b4e60b91451e7ea7f6a041b0335233047c6242 100755 --- a/tools/testing/selftests/net/netfilter/nft_flowtable.sh +++ b/tools/testing/selftests/net/netfilter/nft_flowtable.sh @@ -127,6 +127,8 @@ ip -net "$nsr1" addr add fee1:2::1/64 dev veth1 nodad ip -net "$nsr2" addr add 192.168.10.2/24 dev veth0 ip -net "$nsr2" addr add fee1:2::2/64 dev veth0 nodad +ip netns exec "$nsr1" sysctl net.ipv6.conf.all.forwarding=1 > /dev/null +ip netns exec "$nsr2" sysctl net.ipv6.conf.all.forwarding=1 > /dev/null for i in 0 1; do ip netns exec "$nsr1" sysctl net.ipv4.conf.veth$i.forwarding=1 > /dev/null ip netns exec "$nsr2" sysctl net.ipv4.conf.veth$i.forwarding=1 > /dev/null @@ -153,7 +155,9 @@ ip -net "$ns1" route add default via dead:1::1 ip -net "$ns2" route add default via dead:2::1 ip -net "$nsr1" route add default via 192.168.10.2 +ip -6 -net "$nsr1" route add default via fee1:2::2 ip -net "$nsr2" route add default via 192.168.10.1 +ip -6 -net "$nsr2" route add default via fee1:2::1 ip netns exec "$nsr1" nft -f - <<EOF table inet filter { @@ -352,8 +356,9 @@ test_tcp_forwarding_ip() local nsa=$1 local nsb=$2 local pmtu=$3 - local dstip=$4 - local dstport=$5 + local proto=$4 + local dstip=$5 + local dstport=$6 local lret=0 local socatc local socatl @@ -363,12 +368,12 @@ test_tcp_forwarding_ip() infile="$nsin_small" fi - timeout "$SOCAT_TIMEOUT" ip netns exec "$nsb" socat -4 TCP-LISTEN:12345,reuseaddr STDIO < "$infile" > "$ns2out" & + timeout "$SOCAT_TIMEOUT" ip netns exec "$nsb" socat -${proto} TCP${proto}-LISTEN:12345,reuseaddr STDIO < "$infile" > "$ns2out" & lpid=$! busywait 1000 listener_ready - timeout "$SOCAT_TIMEOUT" ip netns exec "$nsa" socat -4 TCP:"$dstip":"$dstport" STDIO < "$infile" > "$ns1out" + timeout "$SOCAT_TIMEOUT" ip netns exec "$nsa" socat -${proto} TCP${proto}:"$dstip":"$dstport" STDIO < "$infile" > "$ns1out" socatc=$? wait $lpid @@ -394,8 +399,11 @@ test_tcp_forwarding_ip() test_tcp_forwarding() { local pmtu="$3" + local proto="$4" + local dstip="$5" + local dstport="$6" - test_tcp_forwarding_ip "$1" "$2" "$pmtu" 10.0.2.99 12345 + test_tcp_forwarding_ip "$1" "$2" "$pmtu" "$proto" "$dstip" "$dstport" return $? } @@ -403,6 +411,9 @@ test_tcp_forwarding() test_tcp_forwarding_set_dscp() { local pmtu="$3" + local proto="$4" + local dstip="$5" + local dstport="$6" ip netns exec "$nsr1" nft -f - <<EOF table netdev dscpmangle { @@ -413,7 +424,7 @@ table netdev dscpmangle { } EOF if [ $? -eq 0 ]; then - test_tcp_forwarding_ip "$1" "$2" "$3" 10.0.2.99 12345 + test_tcp_forwarding_ip "$1" "$2" "$pmtu" "$proto" "$dstip" "$dstport" check_dscp "dscp_ingress" "$pmtu" ip netns exec "$nsr1" nft delete table netdev dscpmangle @@ -430,7 +441,7 @@ table netdev dscpmangle { } EOF if [ $? -eq 0 ]; then - test_tcp_forwarding_ip "$1" "$2" "$pmtu" 10.0.2.99 12345 + test_tcp_forwarding_ip "$1" "$2" "$pmtu" "$proto" "$dstip" "$dstport" check_dscp "dscp_egress" "$pmtu" ip netns exec "$nsr1" nft delete table netdev dscpmangle @@ -441,7 +452,7 @@ fi # partial. If flowtable really works, then both dscp-is-0 and dscp-is-cs3 # counters should have seen packets (before and after ft offload kicks in). ip netns exec "$nsr1" nft -a insert rule inet filter forward ip dscp set cs3 - test_tcp_forwarding_ip "$1" "$2" "$pmtu" 10.0.2.99 12345 + test_tcp_forwarding_ip "$1" "$2" "$pmtu" "$proto" "$dstip" "$dstport" check_dscp "dscp_fwd" "$pmtu" } @@ -455,7 +466,7 @@ test_tcp_forwarding_nat() [ "$pmtu" -eq 0 ] && what="$what (pmtu disabled)" - test_tcp_forwarding_ip "$nsa" "$nsb" "$pmtu" 10.0.2.99 12345 + test_tcp_forwarding_ip "$nsa" "$nsb" "$pmtu" 4 10.0.2.99 12345 lret=$? if [ "$lret" -eq 0 ] ; then @@ -465,7 +476,7 @@ test_tcp_forwarding_nat() echo "PASS: flow offload for ns1/ns2 with masquerade $what" fi - test_tcp_forwarding_ip "$1" "$2" "$pmtu" 10.6.6.6 1666 + test_tcp_forwarding_ip "$1" "$2" "$pmtu" 4 10.6.6.6 1666 lret=$? if [ "$pmtu" -eq 1 ] ;then check_counters "flow offload for ns1/ns2 with dnat $what" @@ -487,7 +498,7 @@ make_file "$nsin_small" "$filesize_small" # Due to MTU mismatch in both directions, all packets (except small packets like pure # acks) have to be handled by normal forwarding path. Therefore, packet counters # are not checked. -if test_tcp_forwarding "$ns1" "$ns2" 0; then +if test_tcp_forwarding "$ns1" "$ns2" 0 4 10.0.2.99 12345; then echo "PASS: flow offloaded for ns1/ns2" else echo "FAIL: flow offload for ns1/ns2:" 1>&2 @@ -495,6 +506,14 @@ else ret=1 fi +if test_tcp_forwarding "$ns1" "$ns2" 0 6 "[dead:2::99]" 12345; then + echo "PASS: IPv6 flow offloaded for ns1/ns2" +else + echo "FAIL: IPv6 flow offload for ns1/ns2:" 1>&2 + ip netns exec "$nsr1" nft list ruleset + ret=1 +fi + # delete default route, i.e. ns2 won't be able to reach ns1 and # will depend on ns1 being masqueraded in nsr1. # expect ns1 has nsr1 address. @@ -520,7 +539,7 @@ table ip nat { EOF check_dscp "dscp_none" "0" -if ! test_tcp_forwarding_set_dscp "$ns1" "$ns2" 0 ""; then +if ! test_tcp_forwarding_set_dscp "$ns1" "$ns2" 0 4 10.0.2.99 12345; then echo "FAIL: flow offload for ns1/ns2 with dscp update and no pmtu discovery" 1>&2 exit 0 fi @@ -546,7 +565,7 @@ ip netns exec "$ns2" sysctl net.ipv4.ip_no_pmtu_disc=0 > /dev/null ip netns exec "$nsr1" nft reset counters table inet filter >/dev/null ip netns exec "$ns2" nft reset counters table inet filter >/dev/null -if ! test_tcp_forwarding_set_dscp "$ns1" "$ns2" 1 ""; then +if ! test_tcp_forwarding_set_dscp "$ns1" "$ns2" 1 4 10.0.2.99 12345; then echo "FAIL: flow offload for ns1/ns2 with dscp update and pmtu discovery" 1>&2 exit 0 fi @@ -752,7 +771,7 @@ ip -net "$ns2" route del 192.168.10.1 via 10.0.2.1 ip -net "$ns2" route add default via 10.0.2.1 ip -net "$ns2" route add default via dead:2::1 -if test_tcp_forwarding "$ns1" "$ns2" 1; then +if test_tcp_forwarding "$ns1" "$ns2" 1 4 10.0.2.99 12345; then check_counters "ipsec tunnel mode for ns1/ns2" else echo "FAIL: ipsec tunnel mode for ns1/ns2" --- base-commit: aa7ece8adbea8cca27594a0f80c68f6cb708326d change-id: 20251122-nft_flowtable-sh-ipv6-tcp-76f3d28169d1 Best regards, -- Lorenzo Bianconi <lorenzo(a)kernel.org>

2 weeks

2
3
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[PATCH net-next] selftests: af_unix: remove unused stdlib.h include

by Sunday Adelodun

The unix_connreset.c test included <stdlib.h>, but no symbol from that header is used. This causes a fatal build error under certain linux-next configurations where stdlib.h is not available. Remove the unused include to fix the build. Reported-by: kernel test robot <lkp(a)intel.com> Closes: https://lore.kernel.org/r/202511221800.hcgCKvVa-lkp@intel.com/ Signed-off-by: Sunday Adelodun <adelodunolaoluwa(a)yahoo.com> --- tools/testing/selftests/net/af_unix/unix_connreset.c | 1 - 1 file changed, 1 deletion(-) diff --git a/tools/testing/selftests/net/af_unix/unix_connreset.c b/tools/testing/selftests/net/af_unix/unix_connreset.c index bffef2b54bfd..9844e829aed5 100644 --- a/tools/testing/selftests/net/af_unix/unix_connreset.c +++ b/tools/testing/selftests/net/af_unix/unix_connreset.c @@ -14,7 +14,6 @@ */ #define _GNU_SOURCE -#include <stdlib.h> #include <string.h> #include <fcntl.h> #include <unistd.h> -- 2.43.0

2 weeks

2
1
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[RFC PATCH 0/3] Memory Controller eBPF support

by Hui Zhu

From: Hui Zhu <zhuhui(a)kylinos.cn> This series proposes adding eBPF support to the Linux memory controller, enabling dynamic and extensible memory management policies at runtime. Background The memory controller (memcg) currently provides fixed memory accounting and reclamation policies through static kernel code. This limits flexibility for specialized workloads and use cases that require custom memory management strategies. By enabling eBPF programs to hook into key memory control operations, administrators can implement custom policies without recompiling the kernel, while maintaining the safety guarantees provided by the BPF verifier. Use Cases 1. Custom memory reclamation strategies for specialized workloads 2. Dynamic memory pressure monitoring and telemetry 3. Memory accounting adjustments based on runtime conditions 4. Integration with container orchestration systems for intelligent resource management 5. Research and experimentation with novel memory management algorithms Design Overview This series introduces: 1. A new BPF struct ops type (`memcg_ops`) that allows eBPF programs to implement custom behavior for memory charging operations. 2. A hook point in the `try_charge_memcg()` fast path that invokes registered eBPF programs to determine if custom memory management should be applied. 3. The eBPF handler can inspect memory cgroup context and optionally modify certain parameters (e.g., `nr_pages` for reclamation size). 4. A reference counting mechanism using `percpu_ref` to safely manage the lifecycle of registered eBPF struct ops instances. 5. Configuration via `CONFIG_MEMCG_BPF` to allow disabling this feature at build time. Implementation Details - Uses BPF struct ops for a cleaner integration model - Leverages static branch keys for minimal overhead when feature is unused - RCU synchronization ensures safe replacement of handlers - Sample eBPF program demonstrates monitoring capabilities - Comprehensive selftest suite validates core functionality Performance Considerations - Zero overhead when feature is disabled or no eBPF program is loaded (static branch is disabled) - Minimal overhead when enabled: one indirect function call per charge attempt - eBPF programs run under the restrictions of the BPF verifier Patch Overview PATCH 1/3: Core kernel implementation - Adds eBPF struct ops support to memcg - Introduces CONFIG_MEMCG_BPF option - Implements safe registration/unregistration mechanism PATCH 2/3: Selftest suite - prog_tests/memcg_ops.c: Test entry points - progs/memcg_ops.bpf.c: Test eBPF program - Validates load, attach, and single-handler constraints PATCH 3/3: Sample userspace program - samples/bpf/memcg_printk.bpf.c: Monitoring eBPF program - samples/bpf/memcg_printk.c: Userspace loader - Demonstrates real-world usage and debugging capabilities Open Questions & Discussion Points 1. Should the eBPF handler have access to additional memory cgroup state? Current design exposes minimal context to reduce attack surface. 2. Are there other memory control operations that would benefit from eBPF extensibility (e.g., uncharge, reclaim)? 3. Should there be permission checks or restrictions on who can load memcg eBPF programs? Currently inherits BPF's CAP_PERFMON/CAP_SYS_ADMIN requirements. 4. How should we handle multiple eBPF programs trying to register? Current implementation allows only one active handler. 5. Is the current exposed context in `try_charge_memcg` struct sufficient, or should additional fields be added? Testing The selftests provide comprehensive coverage of the core functionality. The sample program can be used for manual testing and as a reference for implementing additional monitoring tools. Hui Zhu (3): memcg: add eBPF struct ops support for memory charging selftests/bpf: add memcg eBPF struct ops test samples/bpf: add example memcg eBPF program MAINTAINERS | 5 + init/Kconfig | 38 ++++ mm/Makefile | 1 + mm/memcontrol.c | 26 ++- mm/memcontrol_bpf.c | 200 ++++++++++++++++++ mm/memcontrol_bpf.h | 103 +++++++++ samples/bpf/Makefile | 2 + samples/bpf/memcg_printk.bpf.c | 30 +++ samples/bpf/memcg_printk.c | 82 +++++++ .../selftests/bpf/prog_tests/memcg_ops.c | 117 ++++++++++ tools/testing/selftests/bpf/progs/memcg_ops.c | 20 ++ 11 files changed, 617 insertions(+), 7 deletions(-) create mode 100644 mm/memcontrol_bpf.c create mode 100644 mm/memcontrol_bpf.h create mode 100644 samples/bpf/memcg_printk.bpf.c create mode 100644 samples/bpf/memcg_printk.c create mode 100644 tools/testing/selftests/bpf/prog_tests/memcg_ops.c create mode 100644 tools/testing/selftests/bpf/progs/memcg_ops.c -- 2.43.0

2 weeks, 1 day

6
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[PATCH] selftests/mm/uffd: initialize char variable to Null

by Ankit Khushwaha

In "uffd-stress.c" & "uffd-unit-tests.c". address of char variable having garbage value (uninitialized) is passed to 'write' syscall triggers warning. uffd-stress.c:246:39: warning: variable 'c' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] uffd-unit-tests.c:581:31: warning: variable 'c' is uninitialized when passed as a const pointer argument here [-Wuninitialized-const-pointer] so the fix is to assign char variable to '\0' to prevent writing of garbage value. Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux(a)gmail.com> --- this warning is raised with clang version 21.1.5 (Fedora 21.1.5-1.fc43). --- tools/testing/selftests/mm/uffd-stress.c | 2 +- tools/testing/selftests/mm/uffd-unit-tests.c | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c index b51c89e1cd1a..700fbaa18d44 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -241,7 +241,7 @@ static int stress(struct uffd_args *args) return 1; for (cpu = 0; cpu < gopts->nr_parallel; cpu++) { - char c; + char c = '\0'; if (bounces & BOUNCE_POLL) { if (write(gopts->pipefd[cpu*2+1], &c, 1) != 1) err("pipefd write error"); diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c index f917b4c4c943..f4807242c5b2 100644 --- a/tools/testing/selftests/mm/uffd-unit-tests.c +++ b/tools/testing/selftests/mm/uffd-unit-tests.c @@ -543,7 +543,7 @@ static void uffd_minor_test_common(uffd_global_test_opts_t *gopts, bool test_col { unsigned long p; pthread_t uffd_mon; - char c; + char c = '\0'; struct uffd_args args = { 0 }; args.gopts = gopts; @@ -759,7 +759,7 @@ static void uffd_sigbus_test_common(uffd_global_test_opts_t *gopts, bool wp) pthread_t uffd_mon; pid_t pid; int err; - char c; + char c = '\0'; struct uffd_args args = { 0 }; args.gopts = gopts; @@ -819,7 +819,7 @@ static void uffd_events_test_common(uffd_global_test_opts_t *gopts, bool wp) pthread_t uffd_mon; pid_t pid; int err; - char c; + char c = '\0'; struct uffd_args args = { 0 }; args.gopts = gopts; @@ -1125,7 +1125,7 @@ uffd_move_test_common(uffd_global_test_opts_t *gopts, { unsigned long nr; pthread_t uffd_mon; - char c; + char c = '\0'; unsigned long long count; struct uffd_args args = { 0 }; char *orig_area_src = NULL, *orig_area_dst = NULL; -- 2.52.0

2 weeks, 1 day

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[PATCH] [PATCH v4] selftests/seccomp: Fix indentation and rebase error logging patch

by Sameeksha Sankpal

v4: - Resending v3 after reviewer feedback (Shuah Khan). - No code changes. - Fixes email formatting and broken threading in earlier versions. v3: - Rebased against upstream seccomp tree. - Fixed indentation to use tabs instead of spaces. - Used scripts/checkpatch.pl to fix warnings. - Removed blank line before Signed-off-by. v2: - Used TH_LOG instead of printf for error logging. - Moved variable declaration to the top of the function. - Applied review suggestions from Kees Cook. v1: - Initial patch to improve error logging in get_proc_stat(). Suggested-by: Kees Cook <kees(a)kernel.org> Signed-off-by: Sameeksha Sankpal <sameekshasankpal(a)gmail.com> --- tools/testing/selftests/seccomp/seccomp_bpf.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 61acbd45ffaa..dbd7e705a2af 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -4508,9 +4508,14 @@ static char get_proc_stat(struct __test_metadata *_metadata, pid_t pid) char proc_path[100] = {0}; char status; char *line; + int rc; snprintf(proc_path, sizeof(proc_path), "/proc/%d/stat", pid); ASSERT_EQ(get_nth(_metadata, proc_path, 3, &line), 1); + rc = get_nth(_metadata, proc_path, 3, &line); + ASSERT_EQ(rc, 1) { + TH_LOG("user_notification_fifo: failed to read stat for PID %d (rc=%d)", pid, rc); + } status = *line; free(line); -- 2.43.0

2 weeks, 1 day

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[PATCH net-next v2] selftests/net: initialize char variable to null

by Ankit Khushwaha

char variable in 'so_txtime.c' & 'txtimestamp.c' were left uninitilized when switch default case taken. which raises following warning. txtimestamp.c:240:2: warning: variable 'tsname' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized] so_txtime.c:210:3: warning: variable 'reason' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized] initializing these variables to NULL to fix this. Signed-off-by: Ankit Khushwaha <ankitkhushwaha.linux(a)gmail.com> --- changelog: v2: change patch name to net-next. v1: https://lore.kernel.org/all/20251124161324.16901-1-ankitkhushwaha.linux@gma… --- tools/testing/selftests/net/so_txtime.c | 2 +- tools/testing/selftests/net/txtimestamp.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/net/so_txtime.c b/tools/testing/selftests/net/so_txtime.c index 8457b7ccbc09..b76df1efc2ef 100644 --- a/tools/testing/selftests/net/so_txtime.c +++ b/tools/testing/selftests/net/so_txtime.c @@ -174,7 +174,7 @@ static int do_recv_errqueue_timeout(int fdt) msg.msg_controllen = sizeof(control); while (1) { - const char *reason; + const char *reason = NULL; ret = recvmsg(fdt, &msg, MSG_ERRQUEUE); if (ret == -1 && errno == EAGAIN) diff --git a/tools/testing/selftests/net/txtimestamp.c b/tools/testing/selftests/net/txtimestamp.c index dae91eb97d69..bcc14688661d 100644 --- a/tools/testing/selftests/net/txtimestamp.c +++ b/tools/testing/selftests/net/txtimestamp.c @@ -217,7 +217,7 @@ static void print_timestamp_usr(void) static void print_timestamp(struct scm_timestamping *tss, int tstype, int tskey, int payload_len) { - const char *tsname; + const char *tsname = NULL; validate_key(tskey, tstype); -- 2.52.0

2 weeks, 1 day

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[PATCH bpf-next v12 0/7] bpf: Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags for percpu maps

by Leon Hwang

This patch set introduces the BPF_F_CPU and BPF_F_ALL_CPUS flags for percpu maps, as the requirement of BPF_F_ALL_CPUS flag for percpu_array maps was discussed in the thread of "[PATCH bpf-next v3 0/4] bpf: Introduce global percpu data"[1]. The goal of BPF_F_ALL_CPUS flag is to reduce data caching overhead in light skeletons by allowing a single value to be reused to update values across all CPUs. This avoids the M:N problem where M cached values are used to update a map on N CPUs kernel. The BPF_F_CPU flag is accompanied by *flags*-embedded cpu info, which specifies the target CPU for the operation: * For lookup operations: the flag field alongside cpu info enable querying a value on the specified CPU. * For update operations: the flag field alongside cpu info enable updating value for specified CPU. Links: [1] https://lore.kernel.org/bpf/20250526162146.24429-1-leon.hwang@linux.dev/ Changes: v11 -> v12: * Dropped the v11 changes. * Stabilized the lru_percpu_hash map test by keeping an extra spare entry, which can be used temporarily during updates to avoid unintended LRU evictions. v10 -> v11: * Support the combination of BPF_EXIST and BPF_F_CPU/BPF_F_ALL_CPUS for update operations. * Fix unstable lru_percpu_hash map test using the combination of BPF_EXIST and BPF_F_CPU/BPF_F_ALL_CPUS to avoid LRU eviction (reported by Alexei). v9 -> v10: * Add tests to verify array and hash maps do not support BPF_F_CPU and BPF_F_ALL_CPUS flags. * Address comment from Andrii: * Copy map value using copy_map_value_long for percpu_cgroup_storage maps in a separate patch. v8 -> v9: * Change value type from u64 to u32 in selftests. * Address comments from Andrii: * Keep value_size unaligned and update everywhere for consistency when cpu flags are specified. * Update value by getting pointer for percpu hash and percpu cgroup_storage maps. v7 -> v8: * Address comments from Andrii: * Check BPF_F_LOCK when update percpu_array, percpu_hash and lru_percpu_hash maps. * Refactor flags check in __htab_map_lookup_and_delete_batch(). * Keep value_size unaligned and copy value using copy_map_value() in __htab_map_lookup_and_delete_batch() when BPF_F_CPU is specified. * Update warn message in libbpf's validate_map_op(). * Update comment of libbpf's bpf_map__lookup_elem(). v6 -> v7: * Get correct value size for percpu_hash and lru_percpu_hash in update_batch API. * Set 'count' as 'max_entries' in test cases for lookup_batch API. * Address comment from Alexei: * Move cpu flags check into bpf_map_check_op_flags(). v5 -> v6: * Move bpf_map_check_op_flags() from 'bpf.h' to 'syscall.c'. * Address comments from Alexei: * Drop the refactoring code of data copying logic for percpu maps. * Drop bpf_map_check_op_flags() wrappers. v4 -> v5: * Address comments from Andrii: * Refactor data copying logic for all percpu maps. * Drop this_cpu_ptr() micro-optimization. * Drop cpu check in libbpf's validate_map_op(). * Enhance bpf_map_check_op_flags() using *allowed flags* instead of 'extra_flags_mask'. v3 -> v4: * Address comments from Andrii: * Remove unnecessary map_type check in bpf_map_value_size(). * Reduce code churn. * Remove unnecessary do_delete check in __htab_map_lookup_and_delete_batch(). * Introduce bpf_percpu_copy_to_user() and bpf_percpu_copy_from_user(). * Rename check_map_flags() to bpf_map_check_op_flags() with extra_flags_mask. * Add human-readable pr_warn() explanations in validate_map_op(). * Use flags in bpf_map__delete_elem() and bpf_map__lookup_and_delete_elem(). * Drop "for alignment reasons". v3 link: https://lore.kernel.org/bpf/20250821160817.70285-1-leon.hwang@linux.dev/ v2 -> v3: * Address comments from Alexei: * Use BPF_F_ALL_CPUS instead of BPF_ALL_CPUS magic. * Introduce these two cpu flags for all percpu maps. * Address comments from Jiri: * Reduce some unnecessary u32 cast. * Refactor more generic map flags check function. * A code style issue. v2 link: https://lore.kernel.org/bpf/20250805163017.17015-1-leon.hwang@linux.dev/ v1 -> v2: * Address comments from Andrii: * Embed cpu info as high 32 bits of *flags* totally. * Use ERANGE instead of E2BIG. * Few format issues. Leon Hwang (7): bpf: Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_array maps bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_hash and lru_percpu_hash maps bpf: Copy map value using copy_map_value_long for percpu_cgroup_storage maps bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_cgroup_storage maps libbpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu maps selftests/bpf: Add cases to test BPF_F_CPU and BPF_F_ALL_CPUS flags include/linux/bpf-cgroup.h | 4 +- include/linux/bpf.h | 35 +- include/uapi/linux/bpf.h | 2 + kernel/bpf/arraymap.c | 29 +- kernel/bpf/hashtab.c | 94 +++-- kernel/bpf/local_storage.c | 27 +- kernel/bpf/syscall.c | 37 +- tools/include/uapi/linux/bpf.h | 2 + tools/lib/bpf/bpf.h | 8 + tools/lib/bpf/libbpf.c | 26 +- tools/lib/bpf/libbpf.h | 21 +- .../selftests/bpf/prog_tests/percpu_alloc.c | 328 ++++++++++++++++++ .../selftests/bpf/progs/percpu_alloc_array.c | 32 ++ 13 files changed, 560 insertions(+), 85 deletions(-) -- 2.51.2

2 weeks, 1 day

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[PATCH net-next v6 0/5] netconsole: support automatic target recovery

by Andre Carvalho

This patchset introduces target resume capability to netconsole allowing it to recover targets when underlying low-level interface comes back online. The patchset starts by refactoring netconsole state representation in order to allow representing deactivated targets (targets that are disabled due to interfaces going down). It then modifies netconsole to handle NETDEV_UP events for such targets and setups netpoll. Targets are matched with incoming interfaces depending on how they were initially bound in netconsole (by mac or interface name). The patchset includes a selftest that validates netconsole target state transitions and that target is functional after resumed. Signed-off-by: Andre Carvalho <asantostc(a)gmail.com> --- Changes in v6: - Rebase on top of net-next to resolve conflicts, no functional changes. - Link to v5: https://lore.kernel.org/r/20251119-netcons-retrigger-v5-0-2c7dda6055d6@gmai… Changes in v5: - patch 3: Set (de)enslaved target as DISABLED instead of DEACTIVATED to prevent resuming it. - selftest: Fix test cleanup by moving trap line to outside of loop and remove unneeded 'local' keyword - Rename maybe_resume_target to resume_target, add netconsole_ prefix to process_resumable_targets. - Hold device reference before calling __netpoll_setup. - Link to v4: https://lore.kernel.org/r/20251116-netcons-retrigger-v4-0-5290b5f140c2@gmai… Changes in v4: - Simplify selftest cleanup, removing trap setup in loop. - Drop netpoll helper (__setup_netpoll_hold) and manage reference inside netconsole. - Move resume_list processing logic to separate function. - Link to v3: https://lore.kernel.org/r/20251109-netcons-retrigger-v3-0-1654c280bbe6@gmai… Changes in v3: - Resume by mac or interface name depending on how target was created. - Attempt to resume target without holding target list lock, by moving the target to a temporary list. This is required as netpoll may attempt to allocate memory. - Link to v2: https://lore.kernel.org/r/20250921-netcons-retrigger-v2-0-a0e84006237f@gmai… Changes in v2: - Attempt to resume target in the same thread, instead of using workqueue . - Add wrapper around __netpoll_setup (patch 4). - Renamed resume_target to maybe_resume_target and moved conditionals to inside its implementation, keeping code more clear. - Verify that device addr matches target mac address when target was setup using mac. - Update selftest to cover targets bound by mac and interface name. - Fix typo in selftest comment and sort tests alphabetically in Makefile. - Link to v1: https://lore.kernel.org/r/20250909-netcons-retrigger-v1-0-3aea904926cf@gmai… --- Andre Carvalho (3): netconsole: convert 'enabled' flag to enum for clearer state management netconsole: resume previously deactivated target selftests: netconsole: validate target resume Breno Leitao (2): netconsole: add target_state enum netconsole: add STATE_DEACTIVATED to track targets disabled by low level drivers/net/netconsole.c | 155 +++++++++++++++++---- tools/testing/selftests/drivers/net/Makefile | 1 + .../selftests/drivers/net/lib/sh/lib_netcons.sh | 35 ++++- .../selftests/drivers/net/netcons_resume.sh | 97 +++++++++++++ 4 files changed, 254 insertions(+), 34 deletions(-) --- base-commit: e2c20036a8879476c88002730d8a27f4e3c32d4b change-id: 20250816-netcons-retrigger-a4f547bfc867 Best regards, -- Andre Carvalho <asantostc(a)gmail.com>

2 weeks, 1 day

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